Flocked protective coverings



March 24, 1970 L. R. ALEXANDER 3,502,207

FLOCKED PROTECTIVE COVERINGS Filed April 19, 1966 2 Shgets-Sheet 1 L H IINVENTOR.

in Oman 6144mm March 24,1970 L. R. ALEXANDER 3,502,207

FLOCKED PROTECT-IVE cow/Emacs 2 Sheets-Sheet 2 Filed April 19, 1966 INVEN TOR. LEON POLL/N ALEXA DER United States Patent 3,502,207 FLOCKEDPROTECTIVE 'COVERINGS Leon Rollin Alexander, Los Angeles, Calif. (9058Walnut St., Bellllower, Calif. 90706) Continuation-impart of applicationSer. No. 191,598, May 1, 1962. This application Apr. 19, 1966, Ser. No.556,250

Int. Cl. C093 7/00; B44d N44 US. Cl. 206-59 12 Claims ABSTRACT OF THEDISCLOSURE CROSS REFERENCES TO RELATED APPLICATIONS This application isa continuation-in-part of my pending application Ser. No. 191,598, filedMay 1, 1962, and now abandoned. A joint application in which I am acoinventor, Ser. No. 706,707, filed Feb. 16, 1968, includes certainsubject matter disclosed in my applications identified above, acontinuation of a joint application Ser. No. 504,407, filed Oct. 24,1965, and now abandoned.

This invention relates to adhesive webs designed to protect finishedsurfaces of sheet metal, plastic, glass and the like, certain of whichare windable into coils for storage and shipping. More particularly itpertains to an improvement in backfacing such an adhesive web with adiscrete layer of randomly deposited flocking in lieu of release coatingthe back face, thereby permitting said web to be wound upon itself intoa roll and unwound therefrom into engaging application with anothersurface. In certain applications the technique eliminates the need for apaper base which is traditional in such products, and thus permits aconstruction which is exceedingly pliant, controllably distensible andnon-distortingly amenable to changes in laminar curvilinearity when usedin the manner described.

Adhesive webs for the described purpose normally consist of a layer ofpressure sensitive adhesive composition applied to one side of a paperweb serving as a base member for the layer of adhesive, the other sidebeing somewhat unified and release coated so as to form a barrierpreventing the ever-tacky adhesive from bonding too securely to the backface of the carrier when it has been wound into a roll. In the use ofnon-creped forms thereof applied to coilable stainless steel strip, suchmasking paper tends to buckle and to become distorted when the coil isunwound and laid fiat, due to the difference in the respectivecircumferences when coiled and the papers lack of compensating pliancy.

In the course of developing such a product, I observed degradation inthe release properties of standard back coatings such as some siliconeswhen subjected to prolonged wound contact with certain pressuresensitive adhesive compositions. It then occurred to me that thechemical aspect of the problem might be circumvented by flocking theback surface of the paper base member in lieu of applying a releasecoating per se. The first reduction to practice gave evidence of thevalidity of the concept. Following this discovery the flocking wasapplied to the back surface of a filmed layer of pressure sensitiveadhesive composition without an interposed base member. This combinationproved not only to be effective, but possessed of highly desirablecharacteristics for the subject purpose.

The following objectives pertinent to the subject invention derive fromthese discoveries.

The first and primary objective of the invention is to provide a pliantprotective covering for metal or plastic sheeting, capable ofnon-buckling adherence thereto when the protected sheeting is subjectedto changes in curvilinearity.

A corollary objective is to increase reliability and to minimize thecost of such protection.

A third object is that the backfacing of coverings of the general classdescribed may be made transiently protective of an unmasked surfacecontraposed thereto as when in coiled contact therewith or when sheetedand stacked.

Another important object is that the exposed backfacing have arelatively low coefiicient of friction to an opposed non-adhesivesurface in order to facilitate the sliding of one fiat length of metalacross another.

A further object, and an additional reason for eliminating any tendencyfor the protective covering either to buckle or to sever, is to preventdamage to the sheeting in consequence thereof by maintaining fulladhesional contact and uniform thicknessed integrity of the protec tivecovering, thereby reducing the likelihood of its being disturbed ordamaged in the handling of the protected sheets.

Still another object is to provide surface protection during fabricationof articles made from such sheeting, including the forming or drawingthereof with the covering in situ wherein it is preferable that it bepliant so as not to resist contraction and thereby cause it to buckle,that it be distensible so as to permit its being stretched, and that itbe smoothly uniform in thickness so as to avoid a patterned imprintunder pressure such as could occur if the covering were creped orcreased.

A still further objective is to simplify perfect lamination by providingcontrolled distensibility since the combining of relativelynon-distensible elements, one of which is as imperfect as paper, oftenrequires a combination of skill, intelligent application of force andpatience.

Another object is to permit winding the self-adhesive protectivecovering into a roll and unwinding it therefrom at the point ofapplication.

Still another objective is the utilization of randomly depositedflocking for multiple purpose, inclusive of its being substituted forrelease coating, providing reinforcement for a supporting film, incombination therewith permitting elimination of paper support elementsand the cost incident to impregnation and/or surface treatments thereof,and additionally providing cushionable protection both for finishedsurfaces and for unmasked surfaces contraposed thereagainst.

Still another object is that the backfacing may be chemically inert topressure sensitive adhesives and releasable therefrom when suchadhesives are suitably structured.

A further object concerns application of the flocked backfacing teachingbroadly to web-based pressure sensitive adhesive product.

A final object is to utilize treated or coated flocking wheneverapplicable as a lesser-afiinitive backfacing for products of thecharacter described.

To illustrate and describe how these and other objects of this inventionmay be accomplished, reference now is made to the accompanying drawingscomprising visual comparisons for clearer illustration of the advantagesof the present invention over the old art.

FIGURE 1 is a side view of conventional masking shee't applied to metalsheeting wound into a coil.

FIGURE 2 is a side view of the same masking sheet and metal sheetingafter being unwound and laid flat.

FIGURE 3 is a side view of a pliant covering embodying the principles ofthis invention and applied similarly to metal sheeting wound into acoil.

FIGURE 4 is a side view of the same covering and metal sheeting afterbeing unwound and laid flat.

FIGURE 5 is a perspective view of a roll of protective covering inaccordance with the' present invention with its flocked back surface indisengageable wound contact with the adhesive surface.

In reference to the drawings, in FIGURE 1 a conventional masking paper 5consisting of a pressure sensitive adhesive layer 6 secured to a basemember 7 such as paper, the opposite or outer surface being coated 8with low-aflinitive material, thereby causing the back face 8 to bereleasable from the frontal surface of the adhesive 6 when the composite5 is unwound from its manufactured roll. In FIGURE 1, said paper 5,concomitant with its having been unwound has been applied as aprotective medium for, and attached to, the finished surface of metalsheet 9 and thence interwound into the shown coil.

In FIGURE 2, in which the several elements are identically partnumbered, the coiled winding has been unreeled and laid flat. The lineardifference in wound mean circumference between the base member 7 and themetal sheet 9 is readily evident by the buckling 15 which occurs whenthe metal is laid flat as shown in the illustration. The excess lengthof the masking paper 5 (as dominated by that of the base member 7)accumulates at spaced intervals, first peaking upward and then tendingto overlay itself and to form triple-thicknessed creases when the metalsheets are stacked one upon another, which can be most troublesome andin some cases injurious to the metal sheet.

It will be apparent that such buckling is a function of linearincompressibility and that of necessity it entails some slippage at theinterface. Bearing in mind this phenomenon, the spaced intervals betweensuch disengaged or raised areas becomes a function of the masking paperslinear or planar stiffness, or its ability to push itself along in aplane parallel to that of the supporting metal sheet, being resisted insuch movement by the strength of the adhesive.

It also will be apparent that whenever the protective backing istensioned by opposite change in curvilinearity, the forces present arereversed as between the basic elements. The negative consequences oftensioning the backing, which applies positive force at the adhesionalinterface, stem from the certain application of such forces in shear,resulting in tension relief of a non-distensible backing either by creepor slippage and withdrawal from the ends of the metal sheet, or bybreakage of the protective mask.

The lessons thus taught, combined with the described discoveries, led tothe preferred embodiment of the invention as illustrated in FIGURES 3and 4, wherein the pliant protective covering 10 consists of a filmedlayer of ever-tacky adhesive composition 11 and a discrete layer offibrous flocking 12 randomly deposited upon, and reliably anchored to,one surface of said composition, the two said layers thus comprising anintegral combination 10 which is both pliant and distensible, onesurface of which is self-adhesionable to the metal sheeting 14 againstwhich it has been applied prior to being wound into the coil shown inFIGURE 3, and from which the protected sheeting later may be unwound andlaid flat into the position shown in FIGURE 4. It will be noted that nobuckling occurs since this type of covering lacks the stiffness whichoccasions such behavior.

FIGURE 5 shows a roll of protective covering 10 with its adhesivesurface 11 being disengaged from wound contact with the flocked backface 13. This figure also should be deemed illustrative of a paper-basedadhesive web having a flocked back face which similarly is disengageablewhen unwound.

Protective coverings for the purposes herein described customarily areapplied in wide widths and often must be removed from large sheets. Suchusage therefore demands relatively low specific adhesion to theprotected surfaces. Since this invention derived from working withadhesive compositions applicable to such purpose, it will be apparent tothose who are skilled in the art that what I claim is quite feasible andeasily accomplished. It will be equally evident that releasability of aflocked backfacing from interwound contact with an ever-tacky adhesivecomposition will become progressively marginal as a direct function ofcold flow. It will be understood therefore that I make no claim to thatwhich obviously is impractical and that only a paucity of cold flow istolerable when such an adhesive composition is subjected to interwoundengagement with the flocking in the manner described.

In order to assist others to practice the herein teachings, includingthose who may be less knowledgeable of the art and to whom it otherwisemight not be obvious, I may say that my work was done initially withcompositions based upon plastic rather than rubberlike polymers. Suchcompositions are ideally suited to the described purposes, especiallysince they are heat-liquefiable and so applicable at 100% solids. Thuswhen utilized in the preferred embodiment previously described, whereinthe flocking constitutes the remainder of the finished product, theadhesionable capacity of the composition may be used advantageously foranchorage of the flocking, thus obviating the need for a separatetie-coating. Prior to being cold set, when the thermoplastic adhesive isperfectly amorphous, anchorage of the flocking is relatively secure,although it is preferable that some imbedment be developed byapplication at moderately elevated temperature which in productionpractice may be done in tandem during the cooling cycle following thefilms formation. It also will be understood that the flocking may beapplied and secured to the back surface of a tensionable film or to thatof paper-supported product by any of the techniques commonly practicedin the art.

Although a number of types of contact sensitive compositions may befound suitable for the applications herein described or for otherapplications wherein the herein teachings may be found to have utility,including either film development or the depositing of a coating layerupon a suitable base member and therein casting the adhesive compositionin solution, emulsion or dispersion form and thereafter drying thecomposition, or thereafter fusing as required in organisols andplastisols, or in heat-liquefiable form and thereafter allowed tosolidify upon cooling, that which presently is preferred for the usagedescribed and utilized in the initial development of the inventioncomprises a heat-liquefiable composition consisting essentially of 20 to25 parts of vinyl chloride-acetate copolymer such as Vinylite VYNS-3and/or VYLF, 75 to parts of polyester plasticizer having a very highmolecular weight such as Fexol R2H, and 1 to 3 parts of stabilizer(s)such as commonly are used in vinyl compositions. It will be noted thatin a given range of such copolymers, that having the higher intrinsicviscosity although requiring more plasticizing will tend to be capableof higher cohesion at a given level of pressure sensitivity. Thereforein the preferred embodiment of the invention, Vinylite VYNS-3 would beselected and the said plasticizer incorporated in approximate ratio of4:1 thereto. To those who are skilled in the art it also will beapparent that even higher-viscositied copolymers may be utilizedadvantageously when suitably plasticized, and wherein disparatetack-producing modifiers may be incorporated to enhance the adhesion ofthe composition. It also will be noted that relatively small amounts ofpigments may be used when desired.

Film thicknesses of. the order of 0.003 to 0.006 inch may be considerednormal in self-supporting films, the required caliper depending upon anumber of factors among which must be included the comparative ratio ofcohesion to surface adhesion, the amount of reinforcing contributed bythe flocking including the depth of imbedment and the orientation of theadhesive-contacting fibrous segments, and the severity of the service towhich the final product will be subjected.

Even though my invention teaches means by which lowaflinitive releasecoatings may be avoided in the class of product described, their usewhen prudence counsels is neither rejected nor excluded. It iscontemplated, in fact, that at least the superficial portions of theflocking may be so coated or treated and thereby made lesser-afiinitiveto the adhesive surface, especially when wound contact therewith mightextract an inordinate number of insecurely attached fibrous segments andthereby so imperfect the adhesive surface as to render it unsuitable forthe intended use. Since many of the more recently introduced polymericcompositions having high adhesion properties also are endowed withexceedingly low cold flow properties, their use in accordance with theherein teachings would be ideal although assuredly demanding of lessenedaffinity for the flocking due to their great adhesive strength.

While the basic principles of this invention have been disclosedhereabove and the presently preferable means for reducing it to practicetaught, described and illustrated, it should be understood that theactual means may be varied widely within the scope of the basic conceptsdisclosed.

I claim as my invention:

1. In combination, a length of sheeting having a finished face andcarrying a protective covering coextensively thereon, said coveringconsisting essentially of a tensionable base member having a layer ofadhesive disposed upon one side and a discrete deposit of flockingsecured to the other side, said adhesive having a surface which isnormally pressure sensitive and adapted to be attached to said face bypressurable contact therewith but to permit said covering to be peeledcleanly therefrom when desired.

2. The combination as described in claim 1, wherein said combination iswound into a coil with said covering separating juxtaposed convolutionsof said sheeting.

3. The combination as described in claim 1, wherein said covering ispliant and distensible, and in which the flocking comprises the solefibrous content.

4. An article of manufacture comprising a length of self-adhesiveprotective covering wound into a roll, said covering consistingessentially of a tensionable base member having a layer of pressuresensitive adhesive disposed upon one side and a discrete deposit offlocking secured to the other side, and wherein superficial portions ofsaid flocking are in wound contact with the apposed surface of saidadhesive which has the property of a paucity of cold flow to permitsubstantial disengagement from said superficial portions when saidcovering is unwound from said roll.

5. The article of manufacture as claimed in claim 4, wherein saidadhesive comprises a heat-liquefiable composition consisting essentiallyof vinyl resin and plasticizer.

6. The article of manufacture as described in claim 4, wherein saidsuperficial portions are coated and adapted thereby to have a reducedaflinity for said adhesive surface.

7. The article of manufacture as described in claim 4, wherein saidcovering is pliant and distensible, and in which the flocking comprisesthe sole fibrous content.

8. In combination, a length of sheet metal and a protective coveringcarried upon one face thereof, said covering comprising a'distensi blefilm base and a discrete layer of flocking, wherein said base consistsof an adhesive composition having the flocking disposed coextensively inand upon one surface, its other surface being normallypressure-sensitive and adapted to be attached to said face bypressureable contact therewith but to permit said covering to be peeledcleanly therefrom when desired.

9. The combination in accordance with claim 8, Wherein the sheet metalcomprises a coilable strip thereof and the combination as described iswound into a coil.

10. A protective covering for sheet metal comprising a distensible filmbase and a discrete deposit of flocking, wherein the film base consistsof an adhesive composition which carries the flocking coextensively inand upon one surface, its other surface being normally pressuresensitive, and wherein said covering is wound into a roll withsuperficial portions of said flocking contacting said other surface andadapted to be unwound therefrom without deleterious effect.

11. The protective covering as claimed in claim 10, wherein saidadhesive composition comprises a heatliquefiable composition consistingessentially of vinyl resin and plasticizer.

12. The protective covering in accordance with claim 10, wherein saidportions of the flocking are coated and adapted thereby to have areduced afiinity for said other surface without deleterious effectthereupon.

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OTHER REFERENCES Katz, Irving, Adhesive Materials, Foster PublishingCo., (1964) p. 71.

WILLIAM D. MARTIN, Primary Examiner B. PIANALTO, Assistant Examiner US.Cl. X.R.

